What is a VBAC?

A vaginal birth after a previous caesarean birth is usually referred to as a VBAC (pronounced ‘vee back’). Some midwives and doctors may still use the older terms ‘trial of labour’ or ‘trial of scar’.

Often women who are pregnant after a previous caesarean would like to have a straightforward labour and birth. Many women have a strong physical and emotional desire to experience labour and have their baby with minimal intervention; it matters to them to have this opportunity if they can. Vaginal birth has physical as well as psychological benefits for both mother and baby. It also avoids the risks associated with anaesthesia and major surgery.

If you are considering a VBAC, you may have some concerns about the process, especially if you have had a difficult birth experience before, leading to the decision for a caesarean birth. Additional restrictions will often be recommended for a VBAC, although evidence shows that the care of a woman in labour after a caesarean with a low horizontal scar on the uterus need not be different from that of any other woman in labour.

VBAC risks?

VBAC is usually safer for the mother than a repeat caesarean because a caesarean itself carries extra risks; for example there is more chance of infection, injury to mother or baby from the operation, staying in hospital longer, pain after having their baby and reduced fertility. There are implications for future pregnancies too, including risks of placental problems, which increase with the number of caesareans a woman has, and a greater risk of needing an emergency hysterectomy (surgical removal of the uterus).

The main difference between VBAC and other vaginal births is a small risk of uterine scar separation. The scar on the uterus can cause a weakness in the uterine wall and the stretching that occurs during pregnancy or the strong contractions of labour can cause the scar to become thin or begin to separate. In practice this happens in only 0.5–2% of women. This is known as ‘scar dehiscence’ and it doesn’t usually cause any problem.

However, if the uterine scar tears open, causing bleeding and other complications, it is called ‘uterine rupture’ and is a serious risk to both mother and baby. This happens in only a very few cases (0.35% of VBAC labours without induction or augmentation). If a uterine rupture happens during labour, the woman needs to have a caesarean section very quickly. An experienced midwife should carefully monitor the baby’s heartbeat and, it has been suggested, the woman’s pulse. This, along with watching for abnormalities such as bleeding, or pain that lasts between contractions, will give early warning of potentially serious problems.

Most caesareans are performed using a low horizontal cut in the uterus. If your caesarean was done differently, you will need more detailed information to make an informed decision.

What if I get pregnant soon after a birth by caesarean?

Research seems to show a small decrease in scar separation rates as the gap between pregnancies increases. However, the risks are tiny in all cases and most mothers who have only a short gap between pregnancies do not encounter problems.

I have had two (or more) previous caesareans – is it still possible for me to go for a VBAC?

It is possible to go for a VBAC after two or more c-sections? The likelihood of women successfully having a vaginal birth after more than one previous caesarean section is about the same as that in women who have had only one previous section, and there is little difference in the risk of uterine rupture.

Will my midwife and obstetrician support me in having a VBAC?

Midwives and obstetricians should be supportive of you having a VBAC, but this does vary among different obstetricians and midwives. If you want a vaginal birth this time, discuss it with those caring for you. Find out whether, in their opinion, there is any reason in this pregnancy why you need a caesarean.

If your midwives and obstetrician are not supportive, you have three options:

Go along with what your midwives and obstetrician advise, if you feel this is best for you.

Ask your midwife or family doctor to refer you to a different obstetrician, or contact your supervisor of midwives to discuss your plans and seek support.

Stay with your current caregivers but decline their advice and choose a vaginal delivery.

Medical staff should support your right to make an informed decision.

What are the chances of having a vaginal birth this time?

Most women who choose a VBAC do succeed in having a vaginal birth. The rate varies a lot between different hospitals, but most record VBAC rates of 70%–90%. There are a number of things you can do to keep birth normal and so maximise your chances of having a vaginal birth – these are exactly the same as for any woman having a baby:

Discuss with your midwife a birth plan, which sets out your requests for support in the choices below.

Allow labour to start naturally without induction (which also avoids increasing the risk of scar problems).

Stay at home for as long as you feel comfortable and confident.

Wait till your waters break spontaneously.

Choose to have the baby’s heartbeat listened to with a stethoscope or a handheld Sonicaid (a ‘Doppler’) rather than being strapped to an electronic fetal heart rate monitor.

Avoid having an oxytocin drip to ‘speed up’ labour.

As long as your labour is progressing, tell your midwife you do not be tied to strict time limits on how long the first or second stage of labour should be.

Keep moving around, changing position, being upright – follow your instincts. If you have one-to-one support throughout your labour, this will also reduce the chance of your having a caesarean. In many maternity units midwives are caring for more than one woman at once, so it may be helpful to have someone with you who can support both you and your partner. This could be a female friend or relative who is confident and relaxed about vaginal delivery, or a trained doula or NCT Birth Companion.

What monitoring is recommended during a VBAC labour?

The National Institute for Health & Clinical Excellence (NICE) caesarean section guideline says continuous electronic fetal monitoring (CEFM) should be offered to women having a VBAC. However, as there have been no reliable studies to find out whether CEFM makes VBAC safer this recommendation is not based on firm evidence.

The Cochrane review of CEFM found that it is no more effective at picking up distress in babies than intermittent monitoring and does not reduce the number of babies that die or have cerebral palsy. Do talk to your midwives and obstetrician about your preferences and views, or if you need more information. Whether you choose to use CEFM or not, it should never be used as a substitute for midwifery support in labour.

Can I choose a VBAC home birth?

Any woman can choose to remain at home to have her baby. The risks of serious problems are not greatly increased by a previous caesarean. However, consider how long it would take for you to be transferred to hospital. Current recommended practice for women with a uterine scar is that they need to be in a setting where the baby can be delivered within 30 minutes if an emergency arises. You might like to talk to the NCT Caesarean Birth/VBAC or Homebirth Co-ordinators.

Further information

NCT's helpline offers practical and emotional support in all areas of pregnancy and early parenthood: 0300 330 0700. We also offer antenatal courses which are a great way to find out more about labour and life with a new baby.